Pauci JRA is the commonest chronic inflammatory arthritis of childhood. The etiology is unknown, well documented but unusually complex HLA gene associations indicate a genetic component in pathogenesis. This proposal tests the hypothesis that HLA interacts with antigen or superantigen to activate specific receptors (TCR) as part of a trimolecular complex. Accordingly, patterns of TCR expression will be sought in affected joints, the specificity for pauci JRA, will be established by comparison with other types of JRA. The laboratory methods to be used include PCR in a semi-quantitative manner and DNA sequencing. Essential to the project is the availability of a large cohort of comprehensive HLA-type patients with pauci JRA in the Children's Hospital Medical Center, as well as synovial fluid and synovial lining obtained during the management of their disease. In establishing roles for TCRs in JRA, these studies will enhance our understanding of the immunopathology of the disease. The knowledge generated by the proposal will have the potential to result in disease- specific therapeutic options, for example the use of TCR-specific monoclonal antibodies to treat the disease, part of the longterm goals of the study.